[PATCH] USB: cleanup of usblp
this fixes
-potential hang by disconnecting through usbfs
-kzalloc
-general cleanup
-micro optimisation in interrupt handlers
It compiles and I am printing.
Signed-off-by: Oliver Neukum <oliver@neukum.name>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
diff --git a/drivers/usb/class/usblp.c b/drivers/usb/class/usblp.c
index dba4cc0..d34848a 100644
--- a/drivers/usb/class/usblp.c
+++ b/drivers/usb/class/usblp.c
@@ -7,6 +7,7 @@
* Copyright (c) 2000 Vojtech Pavlik <vojtech@suse.cz>
# Copyright (c) 2001 Pete Zaitcev <zaitcev@redhat.com>
# Copyright (c) 2001 David Paschal <paschal@rcsis.com>
+ * Copyright (c) 2006 Oliver Neukum <oliver@neukum.name>
*
* USB Printer Device Class driver for USB printers and printer cables
*
@@ -273,13 +274,16 @@
{
struct usblp *usblp = urb->context;
- if (!usblp || !usblp->dev || !usblp->used || !usblp->present)
+ if (unlikely(!usblp || !usblp->dev || !usblp->used))
return;
+ if (unlikely(!usblp->present))
+ goto unplug;
if (unlikely(urb->status))
warn("usblp%d: nonzero read/write bulk status received: %d",
usblp->minor, urb->status);
usblp->rcomplete = 1;
+unplug:
wake_up_interruptible(&usblp->wait);
}
@@ -287,13 +291,15 @@
{
struct usblp *usblp = urb->context;
- if (!usblp || !usblp->dev || !usblp->used || !usblp->present)
+ if (unlikely(!usblp || !usblp->dev || !usblp->used))
return;
-
+ if (unlikely(!usblp->present))
+ goto unplug;
if (unlikely(urb->status))
warn("usblp%d: nonzero read/write bulk status received: %d",
usblp->minor, urb->status);
usblp->wcomplete = 1;
+unplug:
wake_up_interruptible(&usblp->wait);
}
@@ -627,9 +633,8 @@
static ssize_t usblp_write(struct file *file, const char __user *buffer, size_t count, loff_t *ppos)
{
- DECLARE_WAITQUEUE(wait, current);
struct usblp *usblp = file->private_data;
- int timeout, err = 0, transfer_length = 0;
+ int timeout, rv, err = 0, transfer_length = 0;
size_t writecount = 0;
while (writecount < count) {
@@ -641,24 +646,11 @@
}
timeout = USBLP_WRITE_TIMEOUT;
- add_wait_queue(&usblp->wait, &wait);
- while ( 1==1 ) {
- if (signal_pending(current)) {
- remove_wait_queue(&usblp->wait, &wait);
- return writecount ? writecount : -EINTR;
- }
- set_current_state(TASK_INTERRUPTIBLE);
- if (timeout && !usblp->wcomplete) {
- timeout = schedule_timeout(timeout);
- } else {
- set_current_state(TASK_RUNNING);
- break;
- }
- }
- remove_wait_queue(&usblp->wait, &wait);
+ rv = wait_event_interruptible_timeout(usblp->wait, usblp->wcomplete || !usblp->present , timeout);
+ if (rv < 0)
+ return writecount ? writecount : -EINTR;
}
-
down (&usblp->sem);
if (!usblp->present) {
up (&usblp->sem);
@@ -724,7 +716,7 @@
static ssize_t usblp_read(struct file *file, char __user *buffer, size_t count, loff_t *ppos)
{
struct usblp *usblp = file->private_data;
- DECLARE_WAITQUEUE(wait, current);
+ int rv;
if (!usblp->bidir)
return -EINVAL;
@@ -742,26 +734,13 @@
count = -EAGAIN;
goto done;
}
-
- add_wait_queue(&usblp->wait, &wait);
- while (1==1) {
- if (signal_pending(current)) {
- count = -EINTR;
- remove_wait_queue(&usblp->wait, &wait);
- goto done;
- }
- up (&usblp->sem);
- set_current_state(TASK_INTERRUPTIBLE);
- if (!usblp->rcomplete) {
- schedule();
- } else {
- set_current_state(TASK_RUNNING);
- down(&usblp->sem);
- break;
- }
- down (&usblp->sem);
+ up(&usblp->sem);
+ rv = wait_event_interruptible(usblp->wait, usblp->rcomplete || !usblp->present);
+ down(&usblp->sem);
+ if (rv < 0) {
+ count = -EINTR;
+ goto done;
}
- remove_wait_queue(&usblp->wait, &wait);
}
if (!usblp->present) {
@@ -874,11 +853,10 @@
/* Malloc and start initializing usblp structure so we can use it
* directly. */
- if (!(usblp = kmalloc(sizeof(struct usblp), GFP_KERNEL))) {
+ if (!(usblp = kzalloc(sizeof(struct usblp), GFP_KERNEL))) {
err("out of memory for usblp");
goto abort;
}
- memset(usblp, 0, sizeof(struct usblp));
usblp->dev = dev;
init_MUTEX (&usblp->sem);
init_waitqueue_head(&usblp->wait);
@@ -1214,10 +1192,9 @@
{
int retval;
retval = usb_register(&usblp_driver);
- if (retval)
- goto out;
- info(DRIVER_VERSION ": " DRIVER_DESC);
-out:
+ if (!retval)
+ info(DRIVER_VERSION ": " DRIVER_DESC);
+
return retval;
}